The selection should cover the whole line in the editor (like in Qt 4.3), but instead it stops at the last character of the line.

Test case main.cpp to reproduce:
//---------------------------------------
#include <QtGui>

class Text: public QTextEdit
{
public:
Text(QWidget* pParent = 0);
void paintEvent(QPaintEvent *event);
};

Text::Text(QWidget* pParent) : QTextEdit(pParent)
{
this->setLineWrapMode(NoWrap);
this->setPlainText("Hello World\nOla' Mundo");
}

void Text::paintEvent(QPaintEvent *event)
{
QTextEdit::ExtraSelection highlight;
QList<QTextEdit::ExtraSelection> extras;
QList<QTextCursor*> errorCursors;
QTextCursor originalCursor = this->textCursor();
QTextCursor cursor = this->textCursor();

// Mark current line
highlight.cursor = this->textCursor();
highlight.format.setProperty(QTextFormat::FullWidthSelection, true);
highlight.format.setBackground(QColor(0,255,0));
extras << highlight;

// Add extra selections
this->setExtraSelections(extras);

QTextEdit::paintEvent(event);
}

int main(int argc, char *argv[])
{
QApplication app(argc, argv);
Text widget;
widget.show();
return app.exec();
}
//---------------------------------------